van ackeren



March 19, 1929. J, A ACKEREN 1,705,841

COKING- RETORT OVEN Filed June 15, 1921 3 Sheets-Sheet 1 March 19, 1929. J, VAN ACKEREN 1,705,841

GOKING RETORT OVEN Filed June 15, 1921 3 Sheets-Sheet 2 JOSEPH VAN ACKEREN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE KOPPERS COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

COKING RETOR'I' OVEN.

7 Application filed June 15,

This invention comprehends improvements of general utility in the coking'retort oven art; andalso comprehends certain improvements especially applicable to coking retortovens of the well-known cross-regenerative type exemplified in the patent to H. Koppers No. 818,033, dated April 17, 1906.

The invention has for objects to provide a coking retort oven, having, as an important characteristic, an extreme flexibility and accessibility of control of the flow through the flame fines ofrthe heating walls and the regenerators, permitting the flow through the flame fines and regenerators remote from the sides of the oven battery to be regulated and controlled from the bottom of the. regenerators, relatively to and independently of the tion, the length of the coking chambers and heating walls may be increased with a resultantincrease 1n the capacity of each coklng chamber, and yet preserving that substantial quality in flow and uniformity in heating essential to the protection of coke of uniform quality. The above mentioned improvements are attained, moreover, with a construction that affords easyaccess to flow con trol devices that lead directly to the regenerators disposed in the interior of the structure and remote from theside walls of the oven battery, as well as to the regenerators and their flow control devices, that are disposed adjacent to the side walls of the battery. V

in addition to the general objects recited above, the invention has for further objects such other improvements or advantages in construction and operation as are found to obtain in the structures and devices hereinafter described or claimed. j

In the accompanying drawings, forming a part of this specificationpand showing, for purposes of exemplification, a preferred form and manner inwhich the invention may be embodied and practiced, but without-limit- 1921. Serial No. 477,657.

ing the claimed invention specifically to such illustrative instance or instances:

Figure l is a crosswise section through a heating wall and regenerators of a coke oven battery embodying features above specified and equipped with the in'iprovements of the present invention, the view being taken ings, the invention is incorporated in a combination coke oven battery, i. e.,-a battery having provision for being operated either with producer gas as the fuel or with coke oven gas. For convenience, the present description will be confined to the present illustrated embodiment of the invention'in'such a combination coke oven battery; the novel fea tures and improvements made by the invention are, however, susceptible of other applications in coke oven batteries of other types, such for example, as ordinary so-called coke ovens employing coke oven gas as the fuel,

or ordinary so-called gas ovens employing producer gas or other extraneously derived gas as the fuel; hence, the scope of the invention is not confinedto the specific use and specific embodiment herein described as an illustrative example.

Referring to the drawings: there are illustrated views of acoke oven battery or plant of the by-product type, having features above specified, and said oven battery embodies in its construction a plurality of crosswise elongated vertical heating walls 11, 11, and a plurality of intermediate crosswise elongated vertical coking chambers or ovens 12, 12. The heatingwalls 11 form the sidewalls of the respective coking chambers 12, as shown more particularly in Fig. 2, and in the present instance are supported by the heavy supporting or pillar walls 13, 13, which extend crosswise of the battery and are located. as shown in Fig. 2, beneath the respective heating Walls entire battery rests.

The coal to be coked is charged into the several coking chambers or ovens through charging holes indicated by dotted lines at 17, such charging holes being located in the top 18 of the oven battery and positioned directly above the ovens or chambers 12, as shown in Fig. 2. These charging holes 17 are equipped with the usual removable covers, which are removed during charging of the individual ovens or coking chambers and are placed in position to close the tops of such coking ch ambers during the entire coking or distilling operation. The gases of distillation pass from the tops of the several coking chambers or retorts 12 through the usual gas outlets (not shown) and thence through ascension pipes (not shown) to the usual collecting main which carries the gasesto the by-product recovery apparatus.

The heat for coking the charges of coal in the several ovens or chambers 12 is derived from the heating walls 11, which, as before mentioned, extend crosswise of the battery at the sides of the coking chambers. Referring now more particularly to Fig. 1, each heating wall 11 is constituted of a plurality of flame 'orcombustion flues 19. The flame flues of each heatlng wall are, in accordance Wltil the invention, operatively disposed into three series, a middle or interior series of flues A and side series of flues B andC respectively extending from the opposite ends of the aforesaid middle series A to the opposite side walls of the battery. In the operation of the batteryfeach series A, B and C of heating flues is'oper'atively disposed into two groups G and H. Consequently there are three groups of flues disposed on each side. of the central line T of the battery, this center line being indicated at about the middle of the heating wall shown in vertical section in Fig. 1.

The crosswise regenerators 20 of the retort oven or battery are located at a lower level than the aforesaid heating walls 11 and coking chambers 12, and, in the present instance, extend in parallelism beneath tie coking chambers and between the pillar walls 13. Below the middle lengthwise line T of the heating walls 11 aforesaid, there is a partition 21, as shown in Fig. 1, which partition extends all the way up from the bottom of the regenerators to the bottom of the overlying coking chamber and from one to the other of each of the pillar walls 13. This partition corresponds in position with the center line T which is located between the inflow and outflow groups of the middle series A of heating flues 19.

According to the invention, there are also disposed between the opposite walls of each adjacent pair of pillar walls 13, and on each side of the central partition 21 similarly constructed partitions 22 and 23 respectively corresponding with the dividing lines between the inflow and outflow-groups G and H of the side series of heating flues A and B. lVith this construction, there are thus formed below each coking chamber and crosswise of the battery four end to end regenerators 20, the meeting ends of which are the partitions 21, 22, and 23. 7

Each regenerator 2O is-a chamber containing open brickwork commonly called checkerwork and indicated at 24, with distributing sole channels 25 underneath the checkerwork of each regenerator, the said channels 25 forming the solesof such chambers and open ing up into the checkerwork of their respective regenerators. These regenerators are heated in alternation by the hot combustion products that are exhausted from the flame or combustion flues hereinbefore mentioned and then impart such heat to the medium that they feed into these flame flues, the preheated medium so fed into the flame or heating flues, according to the coking retort oven illustrated in the drawings, varying with the character of oven operation, as will hereinafter appear.

As shown in Fig. 1, the two inside regenerators beneath each heating wall are designated by the referencecharacters K and L, and the two outside regenerators by the reference characters M and N; the two outside regenerators M and N correspond to and are individually communicably connected respectively with the groups of flame flues Gr and H of the series B and G; and the two inside regenerators K and L correspond to and are communicably connected respectively I with the two adjacently disposed groups of.

flame flues H of the series B and A and the two adjacently disposed groups G r of the series A and 0. Thus the invention provides separate and individual regenerators for the inside flame flues, which are located remotely from the opposite sides of the battery, as

well as for the outside flame flues located adjacent to the sides-of the battery, thereby permitting the separate control of the flow through the aforesaid remotely-positioned inside flues with respect to the flow through the outside flues. The result is that the flow through the inside flues, comprising-the two groups H of the series B and A, and the two groups G of the series A and C, may be regulated andcontrolled independently, of the flow through the outside fines, comprising ing wall.

the group G of the series B and the group H of the series G, of each heating wall, to permit uniformity in flow throughout the heat-- By this construction, flow conditions throughout all the flame flues of a heating wall may be equalized and, because of the individual regenerative connections with the inside flues, the length of the heating wall may be increased beyond the limits of present practice, without impairing the substantial equality in distribution of the flow from end to end of the heating wall. An

increase in length of the heating wall permits a corresponding increase in the length of the coking chamber, with a resultant increase in the capacity of each coking chamber. Moreover, the invention permits great increase in the magnitude of the several di mensions of the oven battery, without necessitating the introduction of regenerator sole channels and inlets or other horizontal collecting or distributing flues of excessive or impracticable cross-section dimensions.

The reversal in flow through the several regenerators of the battery, and also through the groups of flame or combustion flues of the heating walls with which such regenerators are communicably connected, takes place, in

the present embodiment of the invention,

crosswise of the battery in accordance with the mode of operation employed in the coke oven disclosed in thepatent to Koppers above mentioned; Instead, however, of having the entire regenerative space and all the flues on one side of the central partition 21 operate for inflow, while the entire regenerative space and all the flues on the opposite side of said partition are operating for outflow, the outside regenerators M and N on the outer sides of the partitions 22 and 23 operate respective ly as inflow and outflow regenerators, and on reversal respectively as outflow and inflow regenerators;'w11ile the inside regenerators K and L on the opposite sides of the central partition. 21 are operating respectively as outflow and inflow regenerators, and on reversal as inflow and outflow regenerators, the foregoing being the case notwithstanding the medium introduced into the several regenerators. Thus, inflow and outflow are taking place concurrently on each opposite side of the-central partition 21, the flow through the inside regenerator K and outside regenerator =N being concurrently in the same direction,

and the flow through the inside regenerator L and the outside regenerator M being concurrently in the opposite direction with respect to the flow through the aforesaid regenerators K and N. V

In the present instance, each'regenerator communicates with its communicably connected flues 19 of the two heating walls on each side of the regenerator by means of ducts 26, each such duct leading upwardly from a regenerator into a flue. Thus, the outside group G of flues of the series B and the inside group G of the series C together with a group G of the series A operate as upflow or burning flues, when their corresponding regenerators M and L are operating as inflow regenerators; the outside group of flues H of the series C and the two groups H of the two series B and A of each heating wall operate concurrently as downflow flues when their corresponding regenerators N and K are operating as outflow regenerators. On reversal, by means of the reversing connections hereinafter described, the inflow operating regenerators and their communicably connected flues become outflow regenerators and flues, while at the same time the outflow operating regenerators and their communicably connected flues become inflow operating regenerators and fines. If desired, the two inside regenerators 'K and L below each coking chamber may be divided into regenerative compartments by vertical partitions 27 and 28, respectively corresponding in position with the dividing lines between the series B and A of flues and the series A and C of flues.

Each flame flue 19 of each heating wall has at its top a port or opening 29 for draft and the passage of combustion products or waste gas from the flame within the flue.

These ports 29 open up into horizontal or bus J of the fact that it is only necessary for all I the flues of the respective series B, A and C to communicate with each other and the fact that eachsuch series of flues comprises only about one-third the total number of flues ot a heating wall, the'horizontal flues 30 are not required to be of so great capacity as that necessary in present practice and consequently the cross section of area of each horizontal flue 30 may be materially reduced, with. the

result that the thickness and strength of the heating walls are substantially increased in the region ,of the horizontal flues. The horizontal channels or flues 30 above mentioned serve to direct the-exhaust gases-issuing from the ports 2970f the burning flues into the similar ports 29 ofthe outflow operating flues. The draft through thevports 29 may be regulated by means of the usual movable dampers or sliding bricks 31, positioned in the ordinary way in the bottoms of the horizontal flues 30 and adapted to be reached by access flues 32 which extend from the top of the channels 30 in each heating wall to the top 18 of the battery, there being an access flue positioned over each flame or combustion flue of each heating wall.

Extending crosswise of the battery in each 1 pillar wall 13 and located beneath the heating wall 11 thereabove are two pairs of coke oven vgas-supplychannels, the pairs of channels re- 33 anda lower channel 34, both of which are for the purpose of supplying coke oven gas to the several flues on each side of a dividing partition 22 or 23. The two upper channels 33 at the opposite ends of each heating wall communicate with the individual flues 19 of the groups G and H respectively of the series B and O bymeans of ducts that lead from such channels 33 individually into the bottoms ot individual fines; the lower channels 34 respectively supply the two groups H of the series B and A and the two groups of lines G of the'series A. and C and communicate therewith by means of similarly connecting ducts 36. Within the several ducts 35 and 36 are disposed the usual nozzles 37.

The supply of coke oven gas to the channels 33 and 34 of the respective heating walls 11 is derived from coke oven gas mains 38 located, in the present instance, on the opposite sides of the battery and extending longitudinally therealong, as shown. Valvemechanisni, designated generally at 39 is provided on each side of the battery for controlling the supply of coke oven gas to the several channels and 34. Assuming that an oven is operating with coke oven gas as the fuel, the valve mechanism 39 is operated to admit coke oven gas to the upper channels 33 on one side of the battery and to the lower channels 34 on the other side of the battery, the supply of coke oven gas be ing'shut ofi from all other coke oven gas channels on both sides of the battery. On reversal,

, the supply of gas is cut oil from the live coke oven gas supply channels and turned on into the previously deadsupply channels, in accordance with the reversal in direction of flow through the fines 18, as hereinbefore explained.

As shown in the drawings, the sole channels 25 of the several regenerators M, N and compartments of the regenerators K, L of alternate heating Walls are connected by ducts 40 with air valves 41. The ducts 40 respectively extend from the'bottom of their communicably connected regenerators and the air valves 41 are disposed in series, extending crosswise of the battery, as shown in Fig. 1, in the tunnels 14. The bottoms of the several regenerators M, N and compartments oi the regenera' tors K, L, that are intermediate the alternate regenerators aforesaid, are also communicably connected by similar ducts 42 with similarly arranged air valves 43. The ducts 42 and air valves 43 of such intermediate regenerators are, however, employed only when the battery is operating with coke. oven gas. as the fuel, and, when producer gas is employed as :the fuel, the entire series of air valves 43 throughout the battery is closed to prevent air from entering any of the regenerators corresponding to such air valves 43.

Extending longitudinallyof the battery is a producer gas supply main 44 leading from a suitable source of supply of producer gas and extend along opposite sides of the battery,said

stack flues leading to the usual waste gas stack,

for the purpose of conducting'thereto the waste gases from the outflow operating flues and regenerators. Extending crosswise of the battery, within each supporting wall 14 are two pairs ofhorizontal waste gas channels 51 and 52, the waste gas tunnels 51 being communicahly connected with the stack fines 49 by ducts 53 and the waste gas tunnels 52' being connnunicahly connected with the stack flues 50 byducts 54. The bottoms of the several regenerators M and compartments of the several regenerators L throi'lghout the'battery structure are resj iectively communicably connected with the waste tunnels 51 by means of verticaloutflow ducts 55 5 and the bottoms of the com p artments of th e sever a re generators K and the re enerators N,throughout the battery are similarly connected, by meansjof vertical ducts 56 respt-xctively with the waste gas channels ithe this construction, the entire series ot regenerators M and L, throughout the battery, are comi'nunicably connected with generators K and N are coinn'iunicably connected with the stack fines 50. Dampers 57 and 58 are provided in the waste gas channels 51 and 52 for regulating the-outflow therethrough. v j

The operation of the retort oven or battery, when employing an extraneously derived special generator gas, such as ordinary producer gas, as the fuel, is as follows The the stack flues 49, and the entire series of re- V those regenerators which are employed, during the inflow period, for conveying producer gas to the fines. For convenience, the series of alternate regenerators, which alternately feed air to the flues, aredesignated by the reference' character R and the series of interare operating for inflow and that the regenmediate regenerators, which alternately feed producer gas to the flues are designated by the reference character P. Reversal of the flow of producer gas and air in the series of regenerators P and It is eflected by means of a proper operation of the valve control devices 48 and 41, hereinabove described, it being understood that such valve control devices are respectively connected with the usual reversing mechanism for permitting gas and air to flow into the regenerators that are operating for inflow and for shutting off the supply of gas and air to the outflow operating regenerators. Assuming that the regenerators M and L of both series P and R erators K and N of both such series areoperating for outflow, the valves 41 and 48 of the regenerators M and L are open and concurrently the valves 41 and 48 of the regenerators K and M are closed. Producer gas and air flows through the regenerators M and L of the series P and R and entering the groups G of the flue series B, A and C burns upwardly in said flues. The waste gases pass downwardly through the groups H of the flues B, A and C of each heating wall and pass into the regenerators K and N of both series P and R. which operate as outflow regenerators. From the said outflow regenerators, the waste gases pass through the vertical channels 56 and horizontal channels 52 to the stack flues 50. On reversal the inflow regenerators and their communicablyconnected flues become outflow regenerators and the outflow regenerators and their communicably connected flues become inflow regenerators. Consequently the regenerators K and N operate for inflow, with their groups of connected flues H and the waste gases pass through the flues Gr to the regenerators, M. and L of both series P and R to the vertical chan nel's 55 and thence to the horizontal "channels 51 and stack flues 49. I

In operating the oven with coke ovengas, the supply of producer gas to the branch pipes 45 is cut off and air is permitted to flow into such of the regenerators of the series P as are operating for inflow, in place of the producer gas. The supply of coke'oven gas is permitted to flow through the channels 33 and 34 'tosuch of the flues as are operating for inflow, and the valve control devices 41 and 43 are operated at each reversal to-place inflow operating regenerators in communication with the outer air and to cut off the outflow operating regeneratorsfromthe air supply. I

Alternatively, during such coke oven gas operation, some-of the regenerators such as the series P, may be employed for conveying to the flues aneutral gaseous diluent, such as return waste gas, to lengthen the flames in the flues,"in the manner and for thepurpose setforth in the co-pending application for Letters Patent of Joseph Becker, filed April 23, 1920, Serial No. 376,126.

As shown more especially in Fig. 2, horizontal access channels 59 respectively extend from the cross tunnels 15 into the outflow vertical channels 55 and 56. Within each horizontal channel 59 is a damper, such as the slidebrick 60, permitting regulation of the outflow through the vertical channel 55 or 56. The several dampers 60 may be reached from inspection doors provided at the outer ends of the channels 59. These dampers 60 provide regulation for the outflow from the regenerators, such regulation being entirely independent of the regulation of the inflow.

The invention as hereinabove set forth is embodied in a particular form of construction, but may be variously embodied within the scope of the claims hereinafter made.

I claim:

1. In a coking retort oven, in combination: a plurality of coking chambers; heating walls contiguous to said coking chambers and respectively comprising vertical combustion flues arranged in inside and outside groups; separate inside I and outside individually regulable and reversible regenerators extending crosswise of the battery below the coking chambers and the heating walls, the inside regenerators being individually directly con nected with inside groups and the outside regenerators being individually directly connected with outside groups of the aforesaid combustion flues; crosswise walls forming tunnels between them and disposed below said regenerators; a coke oven gas supply mechanism including means for optionally permitting coke oven gas to flow, at each reversal period, into some of the inside and outside groups of combustion flues; reversing valve connections for controlling the flow of air to said regenerators and leading respectively from the bottoms of said re enerators into said tunnels; means for supplying an extraneously derived alternative fuel gas, such as producer gas, to certain of said regenerators, said means including valve connections connected individually with some of the regenerators; a pair of waste gas tunnels eX" tending along each side of the battery; and duct connections leading from some of the regenerators to one pair of said tunnels, and other ductconnections leading from the other regenerators to the other pair of said tunnels; substantially as specified.

2. In a coking retort oven, in combination: a plurality of coking chambers heating walls contiguous to said coking chambers and respectively comprising vertical combustion flues arranged in inside and outside groups; separate inside and outside individually regulableand reversible regenerators eX- tending crosswise of the battery below the coking chambers and the heating walls, the inside regenerators being individually di- I rectly connected with inside groups and the outside regenerators being individually directly connected with outside groups of the aforesaid combustion flues; crosswise walls forming tunnels between them and disposed below said regenerators; reversing valve connections for controlling the flow of air to said regenerators and leading respectively from the bottoms of said. regenerators into said tunnels; means for supplying an extraneously derived fuel gas, such producer gas to certain of said regenerators, said means including valve connections connected individually with some of the regenerators; a pair of waste gas tunnels extending along each side of the battery; and duct connections leading from some of the regenerators to one pair of said tunnels, and other duct connections leading from the other regenerators to the other pair of said tunnels; substantially as specified.

3. In a coking retort oven, in combination: a plurality of coking chambers; heating walls continguous to said coking chambers and respectively comprising vertical combustion flues arranged in inside and outside groups; separate inside and outside individually regulable and reversible regenerators exten ding crosswise of the battery below the coking chambers and the heating walls, the inside regenerators being individually directly connected with inside groups and the outside regenerators being individually directly connected with outside groups of the aforesaid combustion flues; crosswise walls, forming tunnels between them and disposed below said regenerators; a coke oven gas supply mechanism including means for optionally permitting coke oven gas to flow, at each reversal period, into some of the inside and outside groups of combustion flues; reversing valve connections for controlling the flow of air to said regenerators and leading respectively from the bottoms of said regenerators into said tunnels; means for supplying an extraneously derived gas to certain of said regenerators, said means including valve connections connected individually with some of the regenerators; a pair of waste gas tunnels extending along each side of the battery; and duct connections leading from some of the regenerators to one pair of said tunnels, and other duct connections leading from the other regenerators to the other pair of said tunnels; substantially as specified.

i. In a coking retort oven, in combination: a plurality of coking chambers; heating Walls contiguous to said coking chambers and re spectively comprising vertical combustion fines arranged in inside and outside groups; separate inside and outside individually regulable and reversible regenerators extending crosswise of the battery below the coking chambers and the heating walls, the inside regenerators being individually connected with outside groups of the aforesaid combustion fines; crosswise walls forming tunnels between them and dlsposed below said regenerators; and reversing valve connections contiguous to said coking chambers and rcspectively comprising vertical combustion flues arranged n inside and outside groups;

separate inside and outside individually reg ulable and reversible regenerators extending crosswise of the battery below the coking chambers and the heating walls, theinside regenerators being individually connected with outside groups of the aforesaid combustion fines; crosswise walls forming tunnels between them and disposed below said regenerators; reversing valve connections for controlling the flow of the air to said regenerators, and leading respectively from the bottoms of said regenerators into said tunnels; a pair of waste gas tunnels extending along each side of the battery; and duct conncctions leading from some of the regenerator-s to one pair of said tunnels, and other duct connections leading from the other regenerators to the other pair of said tunnels;

substantially, as specified;

6. In a coking retort oven, in combination: a plurality of coking chambers; heatingwalls contiguous to said coking chambers and respectively comprising vertical combustion fiues arranged in inside and outside groups; separate inside and outside individually regulable and reversible regenerators extending crosswise of the battery belowthe coking chambers and the heating walls, the inside regenerators being individually directly connected with inside groups and the outside regenerators being'individually directly connected with outside groups of the aforesaid combustion flues crosswise walls forming tunnels between them and disposed below said regenerators; reversing valve connections for controlling the flow of air to said regenerators, and leading respectively from the bottoms of said regenerators into said tunnels; means forv supplying an extraneously derived fuel gas, such as producer gas to certain of said regenerators, said means in-,

cluding valve connections connected individually with some of the regenerators; apair of waste gas tunnels extending along each side of the battery; and duct connections leading from some of the regenerators to'one pair of said tunnels, and other duct connections leading from the other regenerators to the other piair of said tunnels; substantially as specied. 1 v r a I 7. In a coking retort oven, in combination: a plurality of coking chambers; heating walls contiguous to said coking chambers and respectively comprising vertical combustion flues arranged in inside and outside groups; separate inside and outside individually regulable and reversible regenerators extending crosswise of the battery below the coking chambers and the heating Walls, the inside regenerators being individually directly connected with inside groups and the outside regenerators being individually directly connected with outside groups of the aforesaid combustion flues, the regenerators being jointly operable for conveying air to the flues, or separately operable for conveying to the said flues air and an extraneously de 'ived gas; crosswise walls forming tunnels between them and disposed below said regenerators; and reversing valve connections for controlling the flow of air to said regenerators, and leading respectively from the bottoms of said regenerators into said tunnels; substantially as specified.

8. A coking retort oven,having a plurality of coking chambers, heating walls contiguous to said coking chambers and respectively comprising combustion flues arranged in inside and outside groups, separate inside and outside individually regulable and reversible regenerators extending crosswise of the battery below the coking chambers and heating walls, the said regenerators being individually connected with groups of said.

combustion flues and being jointly operable for conveying air to the fines or separately operable for conveying to the said flues air and an extraneously derived gas, combined with controlling valve connections leading individually into the bottoms of the respective regenerators; substantially as specified.

9. A coking retort even, having a plurality of coking chambers, heating walls contiguous to said coking chambers and respectively comprising a row of combustion flues arranged in inside groups and outside groups, a plurality of the inside groups of flues in one of the rows of combustion flues being connected together for gas flow in series therethrough, separate inside and outside individually regulable and reversible regenerators extending crosswise of the battery below the coking chambers and heating walls, the said regenerators being connected at their tops with the groups of flues, combined with gas flow connections leading individually into the bottoms of the respective regenerators; substantially as specified.

10. A coking retort oven, having a plurality of coking chambers, fluid heating Walls, separate inside and outside individually regulable and reversible regenerators for preheating air and gas and for conveying off the waste gas respectively, said regenerators extending crosswise of the battery and individually communicably connected with the fluid heating walls combined with inflow and outfiow duct connections extending vertically into the bottoms of the individual regenerators and valve means for individually regulating and reversing said regenerators; substantially as specified.

11. A coking retort ovenhaving a plurality of coking chambers, heating walls contiguous to said coking chambers and respectively comprising combustion flues arranged in single outside and in a plurality of pairs of inside groups the individual groups of each of the inside pairs respectively being adapted for flow in the same direction, each pair being adapted for flow in the opposite direction to an adjacent pair or to an adjacent end group; substantially as specified.

12. In the combination defined in claim 11, regenerators substantial y parallel to the heating walls and arranged in single outside and in a plurality of pairs of inside groups corresponding to the groups of the flues of the heatin g walls, each regenerator group being individually connected to its correspond ing flue group and adapted for flow of similar character; substantially as specified.

JOSEPH VAN AOKEREN.

CERTIFICATE OF GORREGTIGN.

Patent No. 1,705,841. Granted March 19. 1929, to

JOSEPH van ACKEREN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page '7, iines 58 and 64, claim 10, for the Word "fluid" read "fined"; and that the said Letters Patent should he read with this correction therein that the same may conform to the record of the case in the Patent ()fiice.

Signed and sealed this 18th day oi June, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

